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    <script>
        // 目标： 编写一个函数，接受一个数组作为参数，并返回数组中所有偶数的和

        let arr = [2, 3, 5, 6, 10, 13, 14]

        function fn(a) {
            let sum = 0
            for(let i = 0; i < a.length; i++) {
                if(a[i] % 2 === 0) sum += a[i]
            }
            return sum
        }
        document.write(fn(arr)); 


    </script>
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